Mechanism Analysis And Research Of Spherical Robot Driven By Omnidirectional Wheel

Spherical robot which has spherical shell and moves by the rolling is a mobile robot.Compared with other mobile robots,the unique advantages of the spherical robot in mechanical structure and motion mechanism make it has wide application prospect in the aspects of life entertainment,industry and military.This paper mainly studies the spherical robot in the aspects of structural design,kinematics and dynamics modeling method,motion simulation experiment analysis and motion control strategy.This paper summarizes the domestic and international work about structure of various spherical robots,and a new structure of spherical robot which is driven by omnidirectional wheel is presented.The structure has a characteristics that the omnidirectional wheel can roll simultaneously in two orthogonal directions to drive the eccentric mass of the ball and can achieve the omnidirectional motion of the spherical robot.Firstly,aiming at the kinematic characteristics of the spherical robot,Euler angle is adopted to describe the position and attitude at any time,the kinematic equation of the spherical robot is established.The position and attitude of the spherical robot in the motion plane is determined.Based on the Newton-Euler method and Lagrange method,the dynamic model of the spherical robot is established,and the changing curve of the state variable of the spherical robot is obtained,which provides a theoretical basis for the motion simulation analysis and motion control study of the spherical robot.Then,the motion law of the spherical robot is studied,based on the virtual prototype model of the omnidirectional wheel driven spherical robot,the linear motion,steering motion,climbing motion and obstacle performance of the spherical robot are theoretically analyzed and simulated.Based on the results of theoretical and simulation analysis,the major factors of the motion state of the spherical robot are summarized.Based on the state space model,the design methods and simulation analysis of the spherical robot controller are studied.By using the pole assignment algorithm,linear quadratic optimal control algorithm of modern control theory,the controller of the omnidirectional wheel driven spherical robot system is designed and simulated,and simulation results show the motion speed of the spherical robot is effectively controlled by the controller.Finally,at the kinematics level,the path tracking control law of the spherical robot is designed by using the backstepping method,and numerical simulation results show that desired path of the spherical robot can be tracked asymptotically by the controller.In this paper,design principles and motion law of the omnidirectional wheel driven spherical robot are grasped fully by the theoretical analysis,numerical solution and simulation experiment analysis.The research process provides a reference for exploring spherical mobile robot.